Rails - Show Action & View for models with one-to-one association? - ruby-on-rails-3

Question

I have a simple app with a User model & an Instructor_Profile model. The associations between these two models is one-to-one. I cannot get my view show.html.erb to render. I am simply trying to display a single attribute from the Instructor_Profile model and I get this error:
NoMethodError in Instructor_profiles#show
undefined method `name' for nil:NilClass
Any help would be greatly appreciated!
Models:
class User
has_one :instructor_profile
class InstructorProfile
belongs_to :user
UsersController:
def new
#user = User.new
end
def create
#user = User.new(params[:user])
if #user.save
UserMailer.welcome_email(#user).deliver
render 'static_pages/congratulations'
else
render 'new'
end
end
InstructorProfilesController:
def new
#instructor_profile = current_user.build_instructor_profile
end
def create
#instructor_profile = current_user.build_instructor_profile(params[:instructor_profile])
if #instructor_profile.save
flash[:success] = "Profile created!"
redirect_to root_path
else
....
end
end
def show
#user = User.find(params[:id])
#instructor_profile = #user.instructor_profile
end
Views/instructor_profiles/show.html.erb:
<p>Display Name: <%= #user.instructor_profile.name %></p>

Answer 1

It happens because #user.instructor_profile is nil.
That means there is no instructor_profile corresponding to the #user.
Please check the create method inside the UserController to confirm whether instructor_profile is creating or not. Code should be something like this,
#user.instructor_profile = InstructorProfile.new(name: "my_name")
#user.instructor_profile.save
edited:
has_one association doesn't mean that every user has to have an instructor_profile. So before you call the #user.instructor_profile.name, just confirm that #user have instructor_profile or not. In your view, you can easily solve this error by adding one condition..
<p>Display Name: <%= #user.instructor_profile ? #user.instructor_profile.name : "no instructor_profile present" %></p>.
One more thing, in instructor_profiles_controller/show, change the code into
#instructor_profile = InstructorProfile.find(params[:id])
#user = #instructor_profile.user